CAREER: Coherent Phonon Control in Iron-Based Superconductors

非技术摘要：高温超导是量子材料中的一种显著现象。理解和控制超导电性是下一代设备处理信息或获取能量的关键。高温超导体的物理性质对其晶体结构极为敏感。定制的激光脉冲可以选择性地控制对材料性能至关重要的结构特征。在某些情况下，激光激发可以创造出具有新功能的晶体结构，这是其他方法不可能实现的。这项研究使用定制的激光脉冲来光学设计铁基超导体的结构。其目的是促进我们对晶体结构与高温超导电性之间关系的认识，并找出控制超导电性的最有效的旋钮。该项目还包括为物理学女研究生、当地女高中生和K-12学生提供广泛的教育和推广计划。这些活动旨在激发人们对实验物理的兴趣，并帮助学生认识到未来材料科学教育和学术生涯的机会。技术摘要：沿着非侵入性和超快的途径控制量子材料的物理性质是开发下一代设备的关键。激光激发声子产生的微小结构微扰可以直接和选择性地改变量子材料的结构参数，这些参数对量子材料的物理性质至关重要。这个项目的目的是通过调节铁-砷/硒的距离来光学研究和操纵铁基超导体中的超导电性和竞争有序。该项目利用长波长激光直接激发晶格模，控制铁-砷/硒的距离，实现在平衡状态下不存在的新相。这种方法的一个理想结果是在高温下稳定瞬时超导电性。这项研究将促进我们对可调谐的相关自由度以及由相干太赫兹场产生的新颖而奇异的相位的了解。用于铁基超导体的方法可以应用于包括铜酸盐、铁电体和多铁性在内的广泛类别的材料，以确定将量子材料引导到所需相的最有效的旋钮。这项研究还对下一代光电设备的开发产生了行业影响，例如可以使用相干太赫兹辐射进行光学工程的超导设备。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical Abstract: High-temperature superconductivity is a remarkable phenomenon found in quantum materials. To understand and control superconductivity is the key to next-generation devices to handle information or harvest energy. The physical properties of high-temperature superconductors are extremely sensitive to their crystal structures. Tailored laser pulses can selectively control structural features which are crucial for materials properties. In certain cases, laser excitation can create crystal structures hosting novel functionalities which are impossible to achieve by other methods. This research uses tailored laser pulses to optically engineer the structure of iron-based superconductors. The goal is to advance our knowledge on the relation between crystal structure and high-temperature superconductivity, and to identify the most efficient knob to control superconductivity. This project also includes broad education and outreach programs for female graduate students in physics, local female high school students, and K-12 students. These activities aim at inspiring excitement about experimental physics, and helping students to recognize opportunities for future education and academic careers in materials science.Technical Abstract: Controlling the physical properties of quantum materials along non-invasive and ultrafast pathways is the key for developing next-generation devices. Small structural perturbations created by laser excitation of phonons can directly and selectively modify structural parameters which are crucial to the physical properties of quantum materials. This project aims at optically investigate and manipulate superconductivity and competing orders in iron-based superconductors by modulating the iron-arsenic/selenium distance. The project uses long-wavelength laser excitation directly targets lattice modes which control the iron-arsenic/selenium distance to realize novel phases which do not exist at equilibrium. A desirable outcome of this approach is stabilizing transient superconductivity at high temperatures. This research will advance our knowledge on the relevant degrees of freedom that can be tuned, and novel and exotic phases which can be generated by coherent terahertz fields. The methods used for iron-based superconductors can be applied to a broad category of materials including cuprates, ferroelectrics and multiferroics to identify the most efficient knob to steer quantum materials to desired phases. The research also has industry impacts on the development of next-generation optoelectronic devices, such as superconducting devices which can be optically engineered using coherent terahertz radiation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.